Vasoocclusion coil with attached fibrous element(s)

ABSTRACT

A device for occluding a blood vessel comprising a helical metal coil having at least one fibrous element attached to its proximal end wherein the fibrous element(s) extends in a sinusoidal wave configuration, the loops of which extend about individual windings at spaced intervals along the axis of the coil.

TECHNICAL FIELD

This invention is in the field of vasoocclusion devices. Moreparticularly it relates to a vasoocclusion coil to which fibrouselements are attached.

BACKGROUND

Vasoocclusion devices are surgical implements that are placed withinvessels, typically via a catheter to block the flow of blood through thevessel. One type of vasoocclusive device is a helical wire coil that haswindings that are dimensioned to engage the walls of the vessels. Fibersare laid crosswise through the windings to provide a substrate forembolization within the vessel. Coils of such structure are availablecommercially from Cook, Inc.

U.S. Pat. No. 4,994,069 describes a vasoocclusive coil that assumes alinear helical configuration when stretched and a folded convolutedconfiguration when relaxed. The stretched condition is used in placingthe coil at the desired site and the coil assumes its relaxedconfiguration--which is better suited to occlude the vessel--once thedevice is so placed.

A principal object of the present invention is to provide a helicalvasoocclusion coil to which fibrous elements are attached in a mannerthat ensures they will not be dislodged from the coil and enhances theability of the coil to facilitate embolization.

DISCLOSURE OF THE INVENTION

The invention is a vasoocclusive device comprising:

(a) a helical coil having a multiplicity of windings extending between afirst end and a second end;

(b) at least one fibrous element having a first end attached to one ofsaid windings in the region of the first end of the coil, a second endattached to another of said windings in the region of the second end ofthe coil, with the portion of the element intermediate said endsextending axially along the coil in a generally serpentine configurationcomposed of a plurality of loops having maxima that extend radiallyoutwardly and minima that extend radially inwardly and are threadedabout individual windings at spaced intervals along the coil.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary elevational view (not to scale) of oneembodiment of the invention.

FIG. 2 is a fragmentary elevational view (not to scale) of anotherembodiment of the invention.

In the drawings, like structures are referred to by the same referencenumeral.

MODES FOR CARRYING OUT THE INVENTION

FIG. 1 depicts one embodiment, generally designated 10, of thevasoocclusive coil of the invention. The device 10 has two components: ahelical coil 11; and a fibrous element 12.

Coil 11 will typically be made of a radiopaque material such asplatinum, tungsten or gold wire. The diameter of the wire will usuallybe in the range of 0.05 to 0.25 mm. The coil has a multiplicity ofindividual windings 13. The axial length of the coil will usually be inthe range of 0.2 to 100 cm, more usually 0.2 to 40 cm and the diameterof the coil will normally be 0.015 to 0.1 cm, more usually 0.025 to 0.1cm. The coil will typically have about 10 to 70 windings per cm, moretypically about 10 to 40 windings per cm.

The fibrous element 12 may be a bundle of individual fibers 14(typically 5 to 100 fibers per bundle, preferably 20 to 30 fibers perbundle) as shown in FIG. 1 or a monofilament 15 as shown in FIG. 2. Thefibers may be made from biocompatible materials such as Dacron(polyethyleneterephthalate), polyglycolic acid, polyactic acid,fluoropolymer (polytetrafluoroethylene), nylon (polyamide), or silk.

In embodiment 10, end 16 of the bundle is tied to winding 17 of the coilby a knot 18. Knotting at the ends of the bundle is desirable, but notessential, as the threading of the loops about the windings (see below)is sufficient to anchor the bundle to the coil. The specific location ofattachment of end 16 is not critical and it will typically be either atthe proximal end 18 of the coil or at a site on the coil spaced from theproximal end a distance greater than the loop length (see below) whenthe loop is lying flat on the coil. The fiber bundle extends in agenerally serpentine or sinusoidal wave configuration along the exteriorof the coil in a series of outer-directed (relative to the coil axis)loops 19 and inner-directed loops 20. The inner-directed loops arethreaded about individual windings, designated 21, 22, 23 and 24 atspaced intervals (indicated as distance "a" between knot 18 and winding21) along the coil. In FIG. 1, the individual windings are shown in aslightly expanded (spaced) condition for the purposes of illustration.More normally, however, the windings will be closer together so that thewindings on either side of windings 21, 22, 23 and 24 pinch the fiberbundle against windings 21, 22, 23 and 24. The length of the intervals("a") between the windings about which the fiber bundle passes may vary.It will typically be about 0.05 to 1 cm. The interval spacing may be thesame or different along the length of the coil. Correspondingly, theloop length (e.g., the curvilinear length of the bundle from knot 18 towinding 21) may vary and may be the same or different from loop-to-loop.The loop length will normally be 0.1 to 2 cm, more usually 0.1 to 0.5cm.

The fibrous element will usually extend between about 10% to 90% of thetotal axial length of coil. In other words the axial distance over whichthe element extends will usually be 0.05 to 90 cm, more usually 0.05 to15 cm. (The dashed lines in the drawings indicate that the coil extendsdistally.) The element will typically be located at the proximal end ofthe wire. In this regard, the term "proximal" is relative to orientationin which the coil is loaded within a catheter. The distal end of theelement is affixed by knot 25 to winding 26.

While FIG. 1 depicts a coil with only a single affixed fiber bundle, itwill be appreciated that a multiplicity (typically 2 to 4) of fiberbundles may be similarly attached at spaced intervals about thecircumference of the coil.

FIG. 2 illustrates another embodiment, generally designated 30, of thevasoocclusive device of the invention. There are two differences betweendevice 10 and device 30: (1) the fibrous element in FIG. 2 is amonofilament 15 and (2) there are two monofilaments 15 attached to thecoil rather than a single fibrous element. As shown, the twomonofilaments are spaced approximately 180° apart about thecircumference of the coil. As in the case of device 10, additionalmonofilaments 15 may be affixed to the coil if desired.

The vasoocclusion coils of this invention are used in a manner similarto the coil of U.S. Pat. No. 4,994,069. Briefly, the coil is preferablysupplied in prepackaged form in a sterile cannula which is adapted toengage the proximal end of a catheter. In this regard the loops of thefibrous bundle will be pressed flat against the coil for placement inthe cannula and catheter. Once the catheter is in place within a vessel,the coil-containing cannula is placed into engagement with the proximalend of the catheter and the coil is transferred from the cannula lumeninto the catheter lumen by exerting force on the proximal end of thecoil. A pusher rod is used to push the coil through the catheter to thedesired coil release site. The location of the coil may be visualizeddue to the radiopacity of the helical coil. Once at the site, the coilis plunged from the catheter lumen into the vessel. This allows theflexible fiber loops to extend outwardly from the coil surface to fillthe vessel.

Modifications of the above-described modes for carrying out theinvention that are obvious to those of skill in the fields of medicaldevice design generally, and vasoocclusion specifically are intended tobe within the scope of the following claims.

We claim:
 1. A vasoocclusive device comprising:(a) a helical coil foroccluding blood flow having a multiplicity of windings extending betweena first end and a second end; (b) at least one fibrous element having afirst end and a second end, with the portion of the element intermediatesaid ends extending axially along the coil in a generally serpentineconfiguration composed of a plurality of loops having maxima that extendradially outwardly and minima that extend radially inwardly and arethreaded about individual windings at spaced intervals along the coil.2. The device of claim 1 wherein the helical coil is from 2 to 100 cm inlength, 0.015 to 0.1 cm in diameter and has about 10 to 70 windings percm.
 3. The device of claim 2 wherein the fibrous element is attached tothe proximal end of the helical coil and extends over about 10% to 90%of the length of the coil.
 4. The device of claim 1 wherein there are amultiplicity of fibrous elements.
 5. The device of claim 1 wherein thereare 1 to 4 fibrous elements.
 6. The device of claim 1 wherein thefibrous element is a bundle of individual fibers.
 7. The device of claim1 wherein the fibrous element is a monofilament.
 8. The device of claim1 wherein the length of an individual loop is 0.1 to 2 cm.
 9. The deviceof claim 1 wherein said spaced interval is about 0.05 to 1 cm in length.10. The device of claim 8 wherein said spaced interval is about 0.05 to1 cm in length.
 11. The device of claim 10 wherein the fibrous elementis a bundle of about 5 to 100 individual fibers, there are 1 to 4fibrous elements, the length of the helica1 coil is 2 to 100 cm, thefibrous elements are affixed to the proximal end of the helical coil,and the fibrous elements extend over about 25% to 50% of the length ofthe coil.
 12. The device of claim 1 wherein the first end of the fibrouselement is attached to one of said windings in the region of the firstend of the coil and the second end is attached to another of saidwindings.
 13. The device of claim 11 wherein the first end of thefibrous element is attached to one of said windings in the region of thefirst end of the coil and the second end is attached to another of saidwindings.